ExxonMobil Chemical offers the broadest range of High Molecular Weight phthalates plasticizers to offer optimal balance of performance and safety. Their compatibility with PVC and low volatility make Jayflex™ the plasticizers of choice when it comes to end products that are required to be durable and safe to use.

How to choose the best plasticizer for PVC and how does it work?

With more than 50 years expertise and R&D in the flexible PVC market, ExxonMobil Chemical is a major global plasticizer producer. ExxonMobil offers the industry’s broadest range of high-molecular-weight (HMW) phthalate plasticizers including branched and linear phthalates but also benzoates, adipates and trimellitates. This range of plasticizers provide the optimal balance of performance and safety to serve almost every flexible PVC end uses, including for example automotive interior, flooring, roofing, wire and cable.
Jayflex™ plasticizers can also be used in polyurethane-based sealants, acrylics, reactive plastisol sealants and underbody coating.

Flexible PVC, a widely used polymer to enhance the quality of our daily life

Many polymers can help produce plastic materials used in various industry segments where tailor-made formulations meet required specifications. Polyvinyl chloride (PVC) is the third largest consumed polymer and one of the most versatile polymers used in rigid, semi-rigid and flexible applications. Flexible PVC offers safety, softness and creativity. Compared to other polymers, PVC is:

Durable

Energy efficient, as it takes less energy to produce than many alternative plastic materials

PVC is a thermoplastic polymer that can be processed and reprocessed to be rigid or flexible, highly valued for its durability making it the material of choice for markets such as building and construction where long life-span of minimum 10 to 20 years and beyond are needed.

Many PVC products are required to be flexible to endure physical stress without breaking and to give specific attributes such as softness, flexibility and extensibility.

How plasticizers make PVC flexible?

Plasticizers are substances that are used in plastics or other materials to impart processability, flexibility, extensibility or other properties to the finished plastic material. Plasticizers make PVC highly flexible and impart the mechanical properties needed in each applications to make PVC soft and easy to shape. The process of plasticization is about developing strong attractive intermolecular forces between PVC and plasticizers (hydrogen bonding, Van Der Waals interaction, dispersion forces,…) brought in by polarity differences.

When the PVC resin is melted and fused, a network of strong physical bonds between individual PVC chains is created resulting in a stiff and rigid plastic material. The addition of plasticizers to PVC before fusion, increases the free volume between PVC chains and weakens the interactions between two adjacent PVC chains. This created free volume allows PVC chains to move past each other, increasing flexibility and extensibility.

Rigid versus Flexible PVC

Most workable plasticizers for PVC are esters for increased interaction with PVC chains. A phthalate is made by reacting an acid (phthalic acid) with two alcohols. The reaction is called esterification. When the acid used is ortho-phthalic acid, the plasticizer is called ortho-phthalate. When the acid used is tere-phthalic acid, the plasticizer is called tere-phthalate. They are isomers of each other: same chemical formula (same density, molecular weight) but different chemical structures. They are both phthalate plasticizers and calling tere-phthalates non-phthalates is not scientifically correct.

What are the key selection drivers for a plasticizer?

The bulk of useful plasticizers are phthalates, in particular ortho-phthalates. They can be divided into low and high molecular weight. Low molecular weight phthalates can be further divided into ortho and tere-phthalates. High molecular weight ortho-phthalates improve your processing and offer a high degree of permanency. There are no high molecular weight tere-phthalates, because they lack sufficient processability and compatibility with PVC. Actually DOTP is process able but not as compatible with PVC. Outside phthalates, several specialty plasticizers are offered to meet different needs, for example aliphthatics like adipates, sebacates, cyclohexanoates; trimelllitates; benzoates; phosphates; citrates; alkyl sulfonate and various specialty esters derived from vegetable oils with different degree of performance, permanence and compatibility but often quite costly.

Of course, not all plasticizer manufacturing processes are the same as some involve either more manufacturing steps or more complex manufacturing steps or different feedstock. As a result, not all plasticizers have the same chemical structure and performance.
Similar to your smartphone, the selection of the right plasticizer out of the large number of commercially available products requires meeting key attributes for a given application.

The first requirement for a plasticizer is to be compatible and permanent. In other words, stay in the finished article. Plasticizers need also to be thermally stable in order to sustain severe thermal processing and aging conditions.

Mixing plasticizers with PVC and processing the mixture need to be cost effective. Plasticizers are processing aids and influence converters processes like extrusion, calendaring, dipping, spread coating,…). Primary plasticizers like DINP, DIDP are versatile, suited to a wide range of applications and processes.

Since over 85 % of the PVC applications are durable (over 10 years lifespan), durability over harsh aging conditions is a key requirement. Therefore UV resistance, migration and extraction resistance of selected plasticizers are key requirements.

Plasticizers need to be safe for use but also safe in use: you have to consider wire insulation or sheathing becoming brittle due to migration or loss of plasticizers.

Finally sustainability gets more and more in the focus. Consumer products and also technical articles have to be sustainable. Life cycle analysis is a mean to evaluate the environmental impact of your products over their life span.

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Case Studies from High Molecular Weight Phthalates Plasticizers

EU scientific agency concludes DINP is not classifiable for reproductive effects. In February 2015, a proposal for the classification of DINP is submitted to the European Chemicals Agency (ECHA) by Denmark. It triggered a scientific debate on the proposal for classification.

Consequently, a complete re-analysis of the raw data on a key study in the dossier conducted by scientists at the Danish Technical University is made.

After 3 years work on the proposals from Denmark to classify DINP as a Category 1B Reproductive Agent, the Risk Assessment Committee (RAC) review process involved a rapporteur and co-rapporteur working in-depth on the Danish proposal one year before the decision was taken by the full committee. In March 2018, the ECHA RAC carried out a robust scientific weight of evidence evaluation taking into account all of the relevant data.